Conditional threshold wear-leveling algorithm for multi-channel NAND flash memory

Recently, NAND flash memory has become a widely-used data storage media. However, it has endurance problem that each NAND flash block has limited erase cycles. The first time erase failure usually occurs when a block has over 10K-100K erase cycles. Wear-leveling is a technique to solve this problem and extend the lifetime of a flash memory. In this paper, a conditional threshold wear-leveling algorithm fitting multi-channel architecture is proposed. The overall wear-leveling operation is separated and distributed to different channels. This reduces the runtime of the wear-leveling operation. The conditional threshold can reduce extra erase operations caused by wear-leveling when the flash memory is young. As the flash memory becomes older, the smaller threshold makes wear-leveling work more frequently to get more even erase cycle distribution.